Ground cover material

ABSTRACT

A woven ground cover sheet material woven from warp and weft tapes and in which the thickness of warp tapes is reduced in longitudinally extending opposite side margins of the material and in one or more centre regions relative to the width of warp tapes making up the balance of the material.

FIELD OF THE INVENTION

The invention relates to woven materials and particularly but not exclusively to woven materials for use as ground covers or other agricultural applications.

BACKGROUND OF THE INVENTION

Ground cover materials are used in agriculture for purposes including moisture retention, water conservation, weed or sward suppression, soil warmth retention, and for light reflecting.

Typically where the material is used primarily as a reflective ground cover for light enhancement, the material is rolled out in lengths onto the ground between rows of trees in an orchard, rows of vines in a vineyard, or rows of berry fruit plants for example, to increase the amount of light to which the plants and in particular fruit are exposed, by reflection of light from the material towards the fruit above. Each length of the material needs to be suitably secured in place such that it will not be dislodged during wind or movement of traffic over the materials. A fastening system including a multiple number of prong fastening components or “claws” may be fixed to thicker edges or side margins of the sheet material by pushing the prongs of the fastening components into the material so that prongs pierce and pass through the material. In turn the prongs are fixed to adjacent trees, or alternatively stakes or pegs inserted for that purpose, typically but not necessarily by a length of elastic cord. The sheet material will typically remain in place for some months, before being removed and reused in a subsequent growing season or on another crop in the same growing season.

Referring to FIG. 3 a a roll of woven fabric material wound around a core/spool/cylinder 4 and ready for dispatch is shown. The fabric is made woven on a loom from warp and weft tapes. If a circular loom is used, the fabric is first made into a tube, then slit at one side along the length of the tube to form a sheet, which is subsequently folded longitudinally in half and wound into a roll about the core 4. If a flat loom is used, the fabric is woven directly into a sheet, and subsequently folded longitudinally in half and wound into a roll on the core 4. The sheet is lengthwise folded before rolling onto the core 4 to reduce the size of the roll for shipping and dispatch.

The warp tapes are the same thickness across the entire material, but are narrower at the side margins (which are both at region 3.1 after folding the material) than the remaining tapes in the warp direction. The roll thickness is hence even as there is no variation in the tape thickness across the warp tapes. The evenness of the warp tapes allows the warp tension to be controlled across the width of the fabric to assist in creating an even fabric.

Referring now to FIG. 3 b, a roll of improved material is shown having side margins 3.2 of increased thickness. In particular the warp tapes are thicker in the side margins, which allows the point of fastening to have greater strength than the other portions of the fabric. The manufacturing process for this material is similar to that described above. However thicker warp tapes at the side margins (which lay adjacent one another once the material is folded) creates a roll as in FIG. 3 b that is difficult to stack. Also the use of thicker warp tapes for the side margins during weaving creates uneven tension on the warp tapes in the weaving machine which in turn generates difficulty in maintaining the overall evenness of the weaving process. Finally, the thicker edges/side margins 3.2, when folded onto each other make it difficult to roll up the length of material evenly (with a constant axis of rotation) which places undesirable stress on the material at the fold line after it has been rolled up.

In FIG. 3 b the tapes at the opposite end to the open end 3.2 are exposed to additional winding pressure as this is where the fold is. This pressure is experienced especially by the weft tapes which are exposed to added winding tension as they are folded over themselves to change direction 180 degrees.

It is an object of the present invention to provide a sheet material that at least partially alleviates the abovementioned difficulty, or to at least provide the public with a useful choice.

SUMMARY OF THE INVENTION

In a first aspect the invention may broadly be said to consist of a ground cover sheet material woven from warp and weft tapes, wherein the material comprises regions of relatively thicker (hereinafter: thicker regions) warp tapes and regions of relatively thinner (hereinafter: thinner regions) warp tapes, the thicker regions being at or adjacent one or both longitudinally extending opposite side margins of the material, and at two or more longitudinally extending centre regions spaced apart on either side of a notional centre or fold line of the material and nearer to the notional centre or fold line of the material than to the longitudinally extending opposite side margins of the material, and the thinner regions making up the balance of the sheet material.

Preferably the two or more longitudinally extending centre regions spaced apart on either side of a notional centre or fold line of the material are between 20 to 100 mm away from the notional centre or fold line.

Preferably the sheet material comprises two side margins on either side of the material of thicker warp tapes and two centre regions of thicker warp tapes spaced apart on either side of the notional centre or fold line of the material. Alternatively the sheet material comprises a single centre region of thicker warp tapes adjacent the notional centre or fold line.

Preferably the warp tapes have a uniform thickness in the thicker regions and a uniform thickness in the thinner regions.

Preferably the warp tapes in the thicker regions are between about 5-300% thicker or more preferably between about 10 and about 200% thicker than the warp tapes in the thinner regions, and even more preferably between about 200 and about 100% thicker.

Preferably the width of each of the thicker regions is up to about 500 mm or more preferably up to about 300 mm. Even more preferably each of the thicker regions is between about 20 and about 300 mm wide and most preferably between about 40 and about 200 mm wide. The width of the side margin may be different from the width of the centre regions on each side of the centre fold line. The centre regions may be between about 20 and about 200 mm, or more preferably between about 30 and about 100 mm, and most preferably between about 40 and about 80 mm in width. While the side margins may be between about 20 and about 300 mm, more preferably between about 40 and about 200 mm, and most preferable between about 60 and about 180 mm in width.

Preferably the width of warp tapes is also decreased in the thicker regions relative to the width of warp tapes in the thinner regions.

In some embodiments the warp tapes in the thicker regions have a width between about 1 and about 4 mm, more preferably between about 2 and about 3 mm and the warp tapes in the thinner regions have a width between about 2 and about 6 mm, more preferably between about 3 and about 5 mm.

In some embodiments the thicker regions have a lower porosity than the thinner regions.

In some embodiments the transition between an inner edge or the inner portion of each side margin and a thinner region of the material is marked by a line or other marking of contrasting colour.

In some embodiments the colour of at least some of the warp tapes in the thicker regions contrasts to that of the balance of the sheet material.

Preferably the warp and weft tapes are of a plastics material.

Preferably the ground cover material is woven from warp tapes and weft tapes which are substantially flat.

Preferably the tapes that the material is woven from are not folded on themselves, so they are placed or inserted into the fabric so there is no placement density to cause folding of the tapes.

In some embodiments the material is made of coloured materials to give a coloured fabric including white, green, black and other colours and even clear with no apparent colour.

In some embodiments the material is reflective of at least about 50% of visible light on at least one side of the material.

In some embodiments some or all tapes of a reflective material are formed from a resin comprising a white pigment, which resin has been formed by mixing a masterbatch consisting essentially of between about 5 and about 90% by weight of a white pigment or combination of pigments, and a first polymer, with a second polymer such that the resin (masterbatch) comprising the white pigment comprises between about 0.5 and about 50% by weight of the total mixture.

Preferably the white pigment is selected from zirconium, dioxide, magnesium, zirconate, calcium zirconate, strontium zirconate, barium zirconate, zirconium silicate, zinc oxide, zinc sulphide, calcium carbonate, barium sulphate, magnesium oxide, titanium dioxide, strontium carbonate, barium carbonate, and potassium titantae.

In some embodiments the material incorporates a compound or compounds added to cause or increase the extent to which the material reflects and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation).

In some embodiments the material incorporates a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation).

In some embodiments the material incorporates a compound or compounds added to cause or increase the extent to which the material reflects and/or absorbs solar radiation.

In some embodiments the material incorporates a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of solar radiation.

Preferably the warp and weft tapes are formed from polyolefin, or an ethylene alpha-olefin, or a polyester, or a biopolymer, or a blend of any of the foregoing.

Typically sheet materials of the invention will be laid out in lengths on the ground between rows of the crop being grown, which may be trees, vines, bushes etc, to increase the amount of light to which the plants and in particular the fruit are exposed, by reflection of the light from the material back up towards the crop above. At the end of a growing season, each length of material is rolled up for storage. The thicker warp tape regions as defined above enable the length of material to roll evenly after use. The particular weight distribution achieved by employing the thicker regions allows the material to maintain alignment as it is rolled-up for storage.

At the time of manufacturing the combination of thicker side margin warp tapes and the thicker warp tapes at the centre region(s) in the even winding up of the roll by ensuring (or supporting) the wind up tension to be more even across all warp tapes. In addition the thicker warp tapes at the centre region(s) reduce(s) the roll up tension on the tapes around the fold line. The latter being especially the case for the weft tapes that are folded at the centre line during manufacture.

The terms “thicker” and “thinner” as used in this specification and claims are relative terms and not intended to be limited to an absolute value or range of thicknesses unless otherwise specified.

The term “comprising” as used in this specification and claims means “consisting at least in part of”. When interpreting each statement in this specification and claims that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner.

It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of example with reference to the accompanying drawings in which:

FIG. 1 shows use of a ground cover material of the invention between two rows of orchard trees;

FIG. 2 shows use of a ground cover material and fixing of the ground cover material in place by the use of a claw and cord system, including a fastening component that penetrates the side margins of the material;

FIG. 3 a shows a possible completed roll of fabric after being rolled but with no thicker side margin or warp tapes on either side of the fold or centre line.

FIG. 3 b shows a possible completed roll of another version of a woven ground cover material with thicker side margin tapes during manufacture;

FIG. 3 c shows a possible complete roll of a woven ground cover material during manufacture in accordance with a preferred embodiment of the invention with thicker side margin and centre region warp tapes;

FIG. 4 a is an enlarged view of a warp tape at the thinner regions of the preferred form ground cover material;

FIG. 4 b is an enlarged view of a warp tape at the thicker regions of the preferred form ground cover material;

FIG. 5 shows a close up view of a section of the woven material of FIG. 1 at a centre region;

FIG. 6 shows a close up view of two centre regions of the woven material of FIG. 1; and

FIG. 7 shows a close up view at a side margin of the woven material of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, agricultural sheeting 1 is shown in use anchored underneath agricultural crops such as rows of orchard trees 12 as a ground cover, which typically has reflective properties to reflect solar radiation onto the fruit trees and fruit from below. Typically long sections of the sheet material are anchored along both edges between rows of orchard trees or vines. The material is woven from flat warp and weft tapes of a plastics material. Referring also to FIG. 2, in use fastening claws 13 connect to the sheeting along its edges, and in turn may connect to clips usually by loops or lengths of extensible or optionally inextensible material. The clips may in turn attach to staples hammered into the spaced trees 12 as shown, or alternatively to stakes or pegs hammered into the ground, or to a wire extending along the row of the trees or vines, or to twine tied around the tree trunk or vine, for example.

The sheet material comprises regions of relatively thicker warp tapes 11 and regions of relatively thinner warp tapes (balance of material). The regions of thicker warp tapes 11 (thicker regions) are at one or both side margins and at least one centre region adjacent to a notional centre or fold line 30 of the material. The regions of thinner warp tapes (thinner regions) make up the balance of the sheet material. In the preferred embodiment, there are thicker warp tapes at both side margins and there are two spaced centre regions of thicker warp tapes as shown in FIG. 1, however, the invention is not intended to be limited to this embodiment. In alternative embodiments there may be more than two or only one centre region of thicker warp tapes and/or only one or two side margin(s) with thicker tapes. The line 30 is preferably along the centre of the material but it will be appreciated that in alternative embodiments, the fold line 30 may not necessarily be exactly at the centre of the material.

Referring to FIG. 3 c, during manufacture, a length of material 3 is woven, then folded and rolled about a spool 4 to form a sheet of material 1 ready for dispatch. As discussed, a flat sheet of material may be first formed directly from a flat loom, or from a circular loom then slit on one side, before being flattened/folded and rolled about the spool 4. The material 3 is woven with thicker warp regions at at least one side margin 28 and at least one centre region 29. The fabric or material in FIG. 3 c is folded (or flattened/closed in the case of a slit tube made from a circular loom) in half prior to being rolled so that the two side margins are on one end of the roll 28 and the other end 29 has the folded section with the one or more centre regions of thicker warp tapes. Only half of the width of the material 3 is visible in FIG. 3 c as the other is folded underneath the first layer, so region 29 is near or adjacent the centre of the material 3. In the preferred embodiment, the other half of the material 3 (not visible as it is folded underneath) is a mirror image of the half shown in FIG. 3 c. Once woven (and cut on one side of the tube into a folded sheet in the case of a circular loom), the sheet can be folded longitudinally at its centre and then rolled up about a spool 4 for efficient dispatch of the material to an end user. By employing one or more thicker warp tape regions 29 at the centre of the sheet 1, the material can be rolled up more evenly to maintain a more even tension across the entire warp during the manufacturing process than if the thicker warp tapes were only on the side margin(s). It will be appreciated, that during manufacture, the material 3 may be rolled about the core or spool 4 any number of times depending on the desired length of the material, but in the preferred embodiment the material is woven around the spool 4 to form a cylinder or roll and then when unwound it can be cut along the length of the roll or cylinder to then form one or more sheets 1 (one of which is shown in FIG. 1) as desired by the end user.

Referring to FIG. 7, a side portion of a sheet of material 1 woven from warp (25 a-c) and weft (25 d) tapes is shown. The warp tapes 25 a towards the side edge 27 a (the cut and seal edge on one side of the fabric) of the sheet material have an increased thickness compared to the warp tapes 25 b at the thinner regions. FIG. 7 shows one side margin 28 a of thicker warp tapes 25 a. The thickness of the warp tapes is mirrored in the opposite side margin (not shown) of the sheet material. The two opposing side margins make up two of the thicker regions of the sheet material that when folded and rolled are on the same side of the fabric in the roll.

Referring now also to FIGS. 5 and 6, the warp tapes 25 a in two centre regions 29 a/b are also thicker than warp tapes 25 b at the thinner regions making up the balance of the sheet material. The two longitudinally extending opposed centre regions 29 a/b are spaced apart and located on either side of a notional longitudinal centre or fold line 30 of the sheet material. The regions 29 a and 29 b are preferably equally separated from either side of the centre line 30. They are placed between 20 to 100 mm away from the centre or fold line. Weft tapes 25 d are common/similar for the entire material or fabric.

Referring now also to FIGS. 4 a and 4 b, typically the warp tapes 25 a in the thicker regions 28/29 of the material have a thickness, T2, that is 5 to 300% or more preferably 10 to 200% or most preferably 20 to 100% more than the thickness, T1, of the warp tapes 25 b at the thinner regions. Most preferably the thicker regions 28 a, 28 b and 29 a, 29 b comprise warp tapes 25 a that are 30 to 50% thicker than the warp tapes 25 b of the thinner regions. Preferably the warp tapes have a uniform thickness, T2, in the thicker regions and a uniform thickness, T1, in the thinner regions.

In one embodiment, the width ‘w’ as in FIG. 7 of each of the thicker regions across the longitudinal axis of the region may be anywhere up to 500 mm wide or more preferably 300 mm. The width ‘w’ may be anywhere between 20 to 300 mm wide or more preferably between 40 to 200 mm wide. The width of the side margin may be different from the width of the centre regions on each side of the centre fold line. The centre regions may be 20 to 200 mm, or more preferably 30 to 100 mm, and most preferably 40 to 80 mm in width. While the side margins may be 20 to 300 mm, more preferably 40 to 200 mm, and most preferable 60 to 180 mm in width. In the most preferred embodiment, each of the thicker regions is 160 mm wide for the side margins 28 a/b and 50 mm wide for the centre regions 29 a/b. The width ‘w’, in the preferred embodiment is larger at the side margins 28 a/b than at the centre regions 29 a/b, however in alternative embodiments, the width ‘w’ may be uniform across all thicker regions 28/29 or different for each region or even wider at the centre region than the side margins.

The thickness, T2, of the side margins 28 a/b (28 b is not shown but is the other side margin of the fabric of FIG. 7) strengthen the side margins of the material, due to the thicker side warp tapes, so that when the sheet is fixed in place using a fixing system 13 (including fastening components in which prongs or similar pierce through the side margins of the material), the increased strength of the material provides more a secure coupling, with reduced risk of tearing or enlargement of the holes formed from prongs piercing through the material. In the preferred embodiment, an indication means is provided to enable a user to easily identify the stronger region 28 a/b of the material. In the preferred embodiment shown, each side margin 28 a/b may be marked with a pair of contrasting coloured warp tapes 25 c that identify a region for inserting a fixing component. In this case 25 c is away from the very edge 27 a of the material or fabric as placement of the fastening device so close to the edge is not recommended. In another embodiment, a single contrasting coloured warp tape is used at the junction between a side margin 28 a/b and an adjacent thinner warp tape region to identify the strengthened area. In yet another alternative, the colour of all thicker warp tapes in the side margins 28 a/b may contrast to those in the adjacent thinner regions. This marker or coloured lines guide the user the best place to attach the fastening device.

Thicker regions 29 a/b along the centre of the sheet are provided to allow the material to roll up evenly after it has been sealed and cut on the edge, 27 a, then flattened or folded during the manufacturing process. This adds convenience and also helps alleviate the stresses on the material at the fold line 30 by allowing the thicker raised tapes to alleviate the winding pressure on the folded centre line of the material or fabric. When the material is folded along its longitudinal centre line 30, the centre region(s) 29 a/b become opposed sides/edges to the thicker side margins 28 a/b. By creating a balance between the thickness of the side margins and the thickness of the material at the fold (i.e. at the centre region(s)), the material is caused to maintain a more constant axis of rotation as it is rolled up to form the balanced roll, ready for efficient stacking and dispatch. The thicker warp tapes at the centre region(s) give a raised area 29 as shown in FIG. 3 c which helps balance the tension created by raised area 28. The thicker warp tapes at the centre therefore assist in roll evenness for stacking and transportation and also evens the tension across the warp tapes during the weaving process.

It will be appreciated that the invention not intended to be limited to the number of centre regions described for the preferred embodiment, but rather is more concerned with providing a balanced thickness/density between the edges of a folded material. In other words, any number of centre regions of thicker warp tapes can be employed adjacent or proximate to (but preferably not at) the centre/fold lines to substantially balance out the thickness of the side margins and allow the material to roll up substantially evenly after it has been folded at the centre/fold line during manufacture. In the preferred embodiment, the thickness of the warp tapes at the centre region(s) and side margins are substantially similar or equal to create this balance. It will be appreciated, that the width of the thicker regions, the relative thicknesses of the warp tapes at the thicker regions, as well as the spacing/distribution of the centre regions are dependent on particular desired properties of the material and can be altered accordingly to provide the above described benefits without departing from the scope of the invention. Preferably the centre regions are closer to the centre or fold line than the side margins of the material.

In the preferred embodiment shown, the warp tapes 25 a in the thicker regions 28/29 of the sheet material respectively have a reduced width, w2, and a higher number of warp tapes per unit area than the thinner regions making up the balance of the sheet material. This allows the advantage of the narrower tapes 25 a to be in the side margins 28 a and 28 b and centre regions 29 a/b and the advantages of wider tapes 25 b to be captured in the remaining parts of the material. The side margins and centre region warp tapes do not have to be narrower than the tapes in 25 b but would be thicker to capture the benefits as already discussed. Typically the width of the warp tapes 25 a in the thicker regions, w2, will be 20-80% of the width, w1, of the warp tapes 25 b of the thinner regions in the balance of the material.

In a particularly preferred form the warp tapes 25 a in thicker regions of the material will be between 1 mm and 4 mm or more preferably between 2 mm and 3 mm in width, while the other warp tapes 25 b will be between 2 mm and 6 mm or more preferably between 3 mm to 5 mm in width. The weft tapes 25 d which extend transversely across the woven material are woven through both the wider warp tapes 25 b and the reduced width warp tapes 25 a at either side margin and at the centre regions of the material. In an alternative embodiment, only the warp tapes 25 a at the side margins 28 a/b may have the reduced width and higher number of warp tapes per unit area but are thicker.

Alternatively the centre region 29 a/b warp tapes 25 a are narrower and the side margin 28 a/b warp tapes 25 a are of the same width as the warp tapes 25 b making up the balance of the material. In another embodiment the tapes are all the same width and difference is only in the tape thickness.

Preferably the ground cover material is woven from warp tapes and weft tapes and wherein the warp and weft tapes are substantially flat. If the tapes are folded then this would generate thicker tapes where they occur but also areas of extra pressure and possible weaknesses of the tapes at the folded areas.

In an alternative embodiment, the thicker warp tape regions are only at the one or more centre regions, and preferably at two centre regions on either side of the fold line 30. In this embodiment, the resulting roll would not be balanced from a winding perspective but the fold line 30 would be protected from high levels of winding pressure or tension.

Preferably the material is reflective of at least 50% or alternatively at least 55% or alternatively at least 60% of visible light on at least one side of the material. In one embodiment of a reflective material the material may reflect at least 40% solar radiation on average across the UV (wavelength about 280-400 nm), visible (wavelength about 400-700 nm) and very near infrared (wavelength about 700-800 nm) ranges, and which transmits at least 10% or 5% on average of solar radiation across the wavelength range about 800-2500 nm. The material may reflect more solar radiation than it transmits and absorbs in the UV, visible, and very near infrared ranges. The material may transmit at least 15% or at least 20% of solar radiation on average in the wavelength range about 800-2500 nm. In another embodiment the material may reflect no UV in the 280 to 300 nm or less than 40% or only 5% of the UV. Some or all tapes of a reflective material may be formed from a resin comprising a white pigment, which resin has been formed by mixing a masterbatch consisting essentially of 5 to 90% by weight of a white pigment or combination of pigments chosen from zirconium, strontium, barium, magnesium, zinc, calcium and titanium pigments, and a first polymer, with a second polymer such that the resin (masterbatch) comprising the white pigment comprises between about 0.5 to 50% by weight of the total mixture. The material could also be made from a premixed formula or compound so there is no polymer to be added and the mixture is then extruded as a compound without a masterbatch. In certain embodiments the white pigment may be selected from zirconium, dioxide, magnesium, zirconate, calcium zirconate, strontium zirconate, barium zirconate, zirconium silicate, zinc sulphide, zinc oxide, calcium carbonate, barium sulphate, magnesium oxide, strontium carbonate, barium carbonate, titanium dioxide and potassium titantae.

In some embodiments the material may incorporate a compound or compounds added to cause or increase the extent to which the material reflects and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation). Thus when the material is placed over or adjunct to plants it will assist in retaining heat beneath the material, which may be desirable for some plants or applications.

In some embodiments the material may incorporate a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation). Thus when the material is placed over or adjacent to plants it will assist in releasing the heat beneath the material, which may be desirable for some plants or applications.

In other embodiments the material may incorporate a compound or compounds added to cause or increase the extent to which the material reflects and/or absorbs solar radiation. Thus when the material is placed over or adjunct to plants it will assist in cooling beneath the material, which may be desirable for some plants or applications.

In other embodiments the material may incorporate a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of solar radiation. Thus when the material is placed over or adjunct to plants it will assist in increasing the heat beneath the material, which may be desirable for some plants or applications.

The tapes may be formed from any suitable polyolefin such as polyethylene or polypropylene, for example, or a mixture thereof, or an ethylene alpha-olefin, or a polyester, or a biopolymer, or a blend of any of the foregoing. Certain plastics are particularly useful when present as minor or major components. Ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA) and ethylene methyl acrylate (EMA) are useful for imparting elasticity and other properties. Polyesters and polystyrene, styrene-butdienie (SB), acrylonitrile-butadienie-styrene (ABS), styrene-aciylonitrile (SAN), polyethylenie terephithialate (PET), polymethylmethacrylate (PMMA) and polycarbonate are useful as dye carriers and also for influencing radiation (reflecting, absorbing and transmission) properties and also other properties on the materials. Starch and other plant polymers are useful to increase biodegradability. Alternatively the tapes may comprise in part or whole of paper, wood or cellulose fibre, starch based polymers, casein, latex or in any combination of the above and/or with petroleum derived plastic polymers. The polymer or polymer blend may incorporate agents such as one or more pigments, UV stabilisers, or processing aids.

The foregoing describes the invention including a preferred form thereof, alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated in the scope hereof as defined in the accompanying claims.

While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow. 

1. A ground cover sheet material woven from warp and weft tapes, wherein the material comprises regions of relatively thicker (hereinafter: thicker regions) warp tapes and regions of relatively thinner (hereinafter: thinner regions) warp tapes, the thicker regions being at or adjacent one or both longitudinally extending opposite side margins of the material, and one or more longitudinally extending centre regions near or adjacent a notional centre or fold line of the material, and the thinner regions making up the balance of the sheet material.
 2. A ground cover sheet material according to claim 1 wherein the thicker regions are at both longitudinally extending opposite side margins on either side of the material.
 3. A ground cover sheet material according to claim 2 and comprising two centre regions of thicker warp tapes spaced apart on either side of the notional centre or fold line of the material.
 4. A ground cover sheet material according to any one of the preceding claims wherein the warp tapes have a uniform thickness in the thicker regions and a uniform thickness in the thinner regions.
 5. A ground cover sheet material according to any one of the preceding claims wherein the warp tapes in the thicker regions are between about 5 and about 300% thicker than the warp tapes in the thinner regions.
 6. A ground cover sheet material according to any one of the preceding claims wherein the warp tapes in the thicker regions are between about 10 and about 200% thicker than the warp tapes in the thinner regions.
 7. A ground cover sheet material according to claim 6 wherein the warp tapes in the thicker regions are between about 20 and about 100% thicker than the warp tapes in the thinner regions.
 8. A ground cover sheet material according to any one of the preceding claims wherein each of the thicker regions is up to about 500 mm wide
 9. A ground cover sheet material according to any one of the preceding claims wherein each of the thicker regions is up to about 300 mm wide.
 10. A ground cover sheet material according to any one of the preceding claims wherein each of the thicker regions is between about 20 and about 300 mm wide.
 11. A ground cover sheet material according to any one of the preceding claims wherein each of the thicker regions is up to about 200 mm wide.
 12. A ground cover sheet material according to any one of the preceding claims wherein each of the thicker regions is about 100 mm wide.
 13. A ground cover sheet material according any one of claim 1 to claim 11 wherein each of the thicker regions is, for the side margins between about 140 and about 180 mm wide, and for the centre regions between about 40 and about 60 mm wide.
 14. A ground cover sheet material according to any one of the preceding claims wherein the width of warp tapes is decreased in the thicker regions relative to the width of warp tapes in the thinner regions.
 15. A ground cover sheet material as claimed in claim 14 in which the warp tapes in the thicker regions have a width between about 1 and about 3 mm and the warp tapes in the thinner regions have a width between about 3 and about 5 mm.
 16. A ground cover sheet material according to any one of the preceding claims wherein the transition between an inner edge of each side margin and a thinner region warp tapes of the material is marked by a line or other marking of contrasting colour.
 17. A ground cover sheet material according to any one of the preceding claims wherein the colour of the warp tapes in the thicker regions contrasts to that of the balance of the sheet material.
 18. A ground cover sheet material according to any one of the preceding claims wherein the warp and weft tapes are of a plastics material.
 19. A ground cover sheet material according to any one of the preceding claims wherein the warp and weft tapes are substantially flat.
 20. A ground cover sheet material as claimed in any one of the preceding claims wherein the material is reflective of at least about 50% of visible light on at least one side of the material.
 21. A ground cover sheet material as claimed in any one of the preceding claims wherein the material is reflective of at least 50% of visible light and about 40% of the UV in the 280 to 400 nm wavelength range on at least one side of the material.
 22. A ground cover sheet material as claimed in any one of the preceding claims wherein some or all tapes of a reflective material are formed from a resin comprising a white pigment, which resin has been formed by mixing a masterbatch consisting essentially of between about 5 and about 90% by weight of a white pigment or combination of pigments, and a first polymer, with a second polymer such that the resin (masterbatch) comprising the white pigment comprises between about 0.5 and about 50% by weight of the total mixture.
 23. A ground cover sheet material as claimed in claim 22 wherein the white pigment is selected from zirconium, dioxide, magnesium, zirconate, calcium zirconate, strontium zirconate, barium zirconate, zirconium silicate, zinc sulphide, zinc oxide, calcium carbonate, barium sulphate, magnesium oxide, strontium carbonate, barium carbonate, titanium dioxide and potassium titantae.
 24. A ground cover sheet material as claimed in either one of claim 22 or claim 23 wherein the material incorporates a compound or compounds added to cause or increase the extent to which the material reflects and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation).
 25. A ground cover sheet material as claimed in either one of claim 22 or claim 23 wherein the material incorporates a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of radiation from the earth (terrestrial (long wave or infrared) radiation).
 26. A ground cover sheet material as claimed in either one of claim 22 or claim 23 wherein the material incorporates a compound or compounds added to cause or increase the extent to which the material reflects and/or absorbs solar radiation.
 27. A ground cover sheet material as claimed in either one of claim 22 or claim 23 wherein the material incorporates a compound or compounds added to cause or increase the extent to which the material allows transmission and/or absorption of solar radiation.
 28. A ground cover sheet material as claimed in claim 18 wherein the warp and weft tapes are formed from polyolefin, or an ethylene alpha-olefin, or polyester, or a biopolymer, or a blend of any of the foregoing.
 29. A ground cover sheet material from warp and weft tapes of a plastics material in which the thickness of warp tapes is increased in: longitudinally extending opposite side margins of the material, and one or more longitudinally extending centre regions near or adjacent a notional longitudinal centre or fold line of the material, relative to the thickness of warp tapes making up the balance of the material.
 30. A ground cover sheet material from warp and weft tapes of a plastics material in which the thickness of warp tapes is increased in: one or more longitudinally extending centre regions near or adjacent a notional longitudinal centre or fold line of the material relative to the thickness of warp tapes making up the balance of the material. 